Awesome Animal Fact - Army Ants

Did you know colonies of army ants build complex nests using their own bodies? Most colonial ants excavate permanent nests in the ground or in structures like dead trees, but army ants make temporary nests with their own bodies!

The name "army ant" actually refers to about 200 species, not all closely related. The name refers to their behavior rather than their lineage. Army ants deploy huge groups of millions of foraging predators. When a group encounters a prey animal, the ants attack in overwhelming numbers. Unlike other ants, army ants are nomadic, frequently on the move. They need to keep moving because they have so many ants in the colony that they quickly deplete the prey in any given area. And this is why they create temporary nests with their own bodies instead of permanent nests.

Army ant colonies alternate between a nomadic phase and a stationary phase. During the nomadic phase, millions of them forage for prey during the day, but each night they form a temporary nest with their bodies, called a bivouac. They usually do this in tree trunks or burrows. The ants grab each others' legs with their powerful mandibles, creating a huge mass that looks kind of like a ball but is actually a complex nest with an orderly structure. The soldier ants stay on the outer surface to protect the colony, and the interior of the living nest has various chambers especially for food, ant larvae, ant eggs, and even a special chamber for the queen.

Astoundingly, most army ant colonies (3-4 million ants) have all come from a single queen—the queen is a serious egg-laying machine. When the queen dies, the entire colony is likely to die because army ants do not have the ability to produce emergency queens. Sometimes, when a colony loses a queen, they will try to locate another related roaming colony that already has a queen and then join with that colony. If the colonies are closely related, they may be allowed to join.

Here is a portion of a complex army ant bivouac.

Photo Credits:
- Army ant bivouac - Geoff Gallice from Gainesville, FL, USA, CC BY 2.0, via Wikimedia Commons